This invention relates to a mining machine and more particularly to a drum-cutter mining machine having at least one sprocket wheel drivingly coupled with a winch while the teeth of the sprocket wheel mesh with teeth of a rack extending along the length of travel by the mining machine.
It is known in the art to provide a drum-cutter mining machine with two sprocket wheels for a drive winch carried by the machine to engage from above a flat-link chain extending along the length of the mine face. A trough with an open top extends along the working face at the side wall of a face conveyor to receive the flat-link chain while a resilient extension from the mining machine extends beneath the chain to insure engagement with the sprocket wheel.
It is also known in the art to provide a rack at the stow side of a face conveyor for engagement with a sprocket of a winch drive carried on a chain drum cutter mining machine to produce the desired advancing movement by the machine along the mine face. However, a proper meshing relation with the sprocket wheel carried on the mining machine cannot always be obtained when the mining machine has a substantial length and moves along a mine floor that is undulating. More particularly, peaks or troughs to the mine floor adversely affect engagement with the sprocket wheel since the mining machine is carried by support skids located at opposite ends of the machine. The usual face conveyor associated with the mining machine is subdivided into relatively short adjoined sections and adaptable to the undulating course of the floor. However, the mining machine, having a structural length which may be 7 meters or greater in length, is not adaptable to the undulating course of the floor. This is because the support skids situated at opposite ends of the machine span a distance whereby four or more conveyor trough sections are bridged by the body of the mining machine. The vertical position of the driven sprocket wheel situated at the longitudinal center of the mining machine cannot be maintained in constant engagement with a rack or flat-link chain because of the constant varying vertical position of the chain or rack relative thereto. When a rack is employed, it is divided into sections and mounted onto the side wall of the face conveyor so that the driven sprocket wheel can produce the desired advancing movement of the mining machine by engaging the rack.